Center Of Pressure Sensor Research Articles

Development of two-dimensional interdigitated center of pressure sensor

This paper presents the development of a two-dimensional (2D) flexible patch sensor to detect and monitor the center of pressure (CoP) location and the total magnitude of a spatially distributed pressure to the specific surface areas of engineering structures. The CoP sensor with the contact mode induced by a pressure distribution was formulated by force sensitive resistor technology and was mainly composed of a thin conductive polymer layer, adhesive spacers, and two interdigitated patterned electrode films with unique sensing aperture shadings. By properly mapping the interdigitated electrode patterns to the top and bottom surfaces of the conductive polymer, the proposed sensor ideally enables to measure an overall applied pressure level and its centroid location within a predetermined sensing region in real-time. The CoP sensor containing 36 sensing sections within a dimension of around 3 × 3 inches was prototyped and experimentally investigated to verify its capability to identify the CoP location and magnitude due to the presence of a permanent magnet-based local pressure distribution. Only five electric wires connected to the CoP sensor to inspect the pressure-sensing positions of 36 segments. The evaluation results of the measured sensor data demonstrate good agreements with the actual test parameters such as the total pressure and its centroid position with about 5% locational error. However, to provide accurate information on the overall pressure range, the compensation factors must be determined and applied to the individual sensing sections of the sensor.

High Speed and High Sensitivity Slip Sensor Utilizing Characteristics of Conductive Rubber - Relationship Between Shear Deformation of Conductive Rubber and Resistance Change -

Humans can grasp an object without information such as a coefficient of friction or weight. To implement this grasping motion with the robot hand, sensors have been proposed that detect an incipient slip within the contact surface or stick-slip. A large number of slip sensors have been proposed, but small, flexible, and practical slip sensors are currently not available yet. We have been involved in research and development activities for a center of pressure (CoP) tactile sensor that is small and flexible. This sensor uses a pressure conductive rubber to detect the central position of the load distribution and total load. As a result of using the sensor to make experiments on slip detection, we found that a peculiar change appeared in the load output of the sensor immediately before the slip displacement of an object occurred. Based on this output change, we proposed a control method that was capable of setting a grasping force in accordance with the weight of an object. However, the principle was not made clear that caused the output change to occur. We hypothesized that the change was caused by the characteristics of the pressure conductive rubber used for the material of the sensor. As a result of making verification experiments based on this hypothesis, we found that the output change was due to a change in the resistance value when the pressure conductive rubber shear deformed. It was also found that the scale of a change in the resistance value was dependent largely upon the shear deformation speed of the pressure conductive rubber. This paper describes the principle that a peculiar change occurs in the CoP sensor immediately before the occurrence of an object slip. It also reports the characteristics of the pressure conductive rubber that have newly been made apparent.

Spatial Weighting of Smart Materials for Real-time Measurement of Aerodynamic Forces

Spatial weighting techniques are used to determine the apertures of a conformal smart material sensor required to measure aerodynamic forces on an aircraft wing section. Aperture shading with a linear weighting allows for the compilation of an aerodynamic center of pressure sensor. A technique is presented that allows the extraction of sectional aerodynamic forces, such as lift and drag, from appropriately shaped sensor electrodes. An example of the implementation of this sensor aperture weighting technique is given for a wing section with a NACA 0010 airfoil cross-section. It is shown that, given any airfoil cross-section, a unique lift and drag sensor aperture can be derived. Preliminary data from the testing of a prototype center of pressure sensor is presented. This sensor technology enables real-time measurement of aerodynamic forces in a free-flight testing environment.

1A2-B07 滑り検出に基づく多指ハンドの把持力制御(触覚と力覚)

To achieve a human like grasping by the multi-fingered robot hand, grasping force should be controlled without information of the grasping object such as the weight and the friction coefficient. In this study, we propose a method for controlling grasping force of multi-fingered robot hand based on slip detection using the Center of Pressure(CoP) tactile sensor. CoP sensor can measure center position of distributed load and total load within 1ms. With the CoP sensor, incipient slip can be detected as the sensor force output signal change before the slip displacement occurs. We propose a method for controlling grasping force based on slip detectionand. It is confirmed that the grasping force can be adjusted to adequate force on the robot hand grasping with the proposed method.

触覚センサによる滑り検出に基づく多指ハンドの把持力制御

To achieve a human like grasping by the multi-fingered robot hand, grasping force should be controlled without information of the grasping object such as the weight and the friction coefficient. In this study, we propose a method for detecting the slip of grasping object by force output of the Center of Pressure (CoP) tactile sensor. CoP sensor can measure center position of distributed load and total load which is applied on the surface of the sensor within 1 [ms] . This sensor is arranged on finger of the robot hand, and the effectiveness as slip detecting sensor is confirmed by experiment of slip detection on grasping. Finally, we propose a method for controlling grasping force resist the tangential force added to the grasping object by feedback control system of the CoP sensor force output.

A PNEUMATIC HUMAN INSPIRED ROBOTIC LEG: CONTROL ARCHITECTURE AND KINEMATICAL OVERVIEW

This paper describes in detail the control architecture of an anthropometric robotic leg. It contains a brief description of the mechanical structure of the prototype and a kinematical structure overview. The aim of this project is the development of new technologies for the implementation and realization of bio-mechanical limbs for motoric gait rehabilitation, as well as for human gate study and analysis. In particular, a detailed description of the pneumatic control architecture is provided, together with some design considerations. Moreover, a platform for walking trajectory generation is presented, and some experimental results are reported. In order to assure a proper stability control during the gait, a center of pressure sensor has been specifically designed and placed onboard the robot. A detailed description on the sensor mechanism is also provided.